As part of an expanding programme of battlefield automation, the American air force has said it is now training more drone operators than fighter and bomber pilots.

In a controversial shift in military thinking – one encouraged by the confirmed death of Pakistani Taliban leader Baitullah Mehsud in a drone-strike on 5 August – the air force is looking to hugely expand its fleet of unmanned aircraft by 2047.

Three years ago, the service was able to fly just 12 drones at a time; now it can fly more than 50. At a trade conference outside Washington last week, military contractors presented a future vision in which pilotless drones serve as fighters, bombers and transports, even automatic mini-drones which attack in swarms.

Five thousand robotic vehicles and drones are deployed in Iraq and Afghanistan. By 2015, the Pentagon’s $230bn (£140bn) arms procurement programme Future Combat Systems expects 15% of America’s armed forces to be robotic.

A recent study ‘The Unmanned Aircraft System Flight Plan 2020-2047’ predicted a boom in drone funding to $55bn by 2020 with the greatest changes coming in the 2040s.

“The capability provided by the unmanned aircraft is game-changing,” said General Norton Schwartz, the air force chief of staff. “We can have eyes 24/7 on our adversaries.”